JPS61153693A - Liquid crystal color display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal color display device using a liquid crystal element as an optical switching element.

Hair bun standing technique! Conventionally, CRT (cathode ray tube) is used as a color display device.
A typical example is one that uses the same technology, and is often used in television display devices and OA (office automation) equipment. However, since CART is a type of large cone-shaped vacuum tube, display devices using CRT require a high-voltage power supply, the drive circuit is complicated, and the entire device must not only be large but also thin. There were limits to this.

In recent years, panel-type liquid crystal display devices using liquid crystals have been actively developed, and here are the recent results.

It has appeared as an LCD color pocket TV. This is the magazine "Nikkei Electronics, 1984, 9-
10. It is described in the article "P, 211-240")'sL-4Lii! f 婁-shi L-ju 螺 Kisanminami 4-
A TN-type liquid crystal is sealed between a glass substrate with a filter and another transparent substrate with an integrated thin film transistor array, and this is sandwiched between two polarizing plates to form a liquid crystal panel. A light source for illumination is placed at the top. Thin film transistors are built to correspond to the red, green, and blue color filters of each pixel, and perform a light switching function.

However, although such liquid crystal color display devices can be made thinner, they use a white lamp as a light source and use optical filters to display color, so the color development and color reproducibility are insufficient, and the contrast is low, making them difficult to see. Moreover, there was a drawback that the power consumption of the illumination light source was large.

An object of the present invention is to provide a liquid crystal color display device that can obtain clear color images with low power consumption.

l Mamedate Toyoshi 1 of the present invention is.

It has a liquid crystal element that controls transmission/blocking of light in accordance with image information, and an electroluminescent light emitting body in which phosphors that emit colored light are arranged and formed in a mosaic pattern in accordance with this element. A liquid crystal color display device characterized in that the light emitted from the light emitter is arranged so as to be observed through the liquid crystal element.

Another aspect of the present invention is that the liquid crystal color display device described above is further provided with a color filter that transmits dazzling light at a position through which light from the electroluminescent light emitter passes.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is an enlarged sectional view schematically showing an embodiment of the present invention. A liquid crystal cell 11 is formed by sealing a liquid crystal substance 19 between an upper substrate 13 and a lower substrate 15 which are disposed to face each other, and a transparent pixel electrode 21 and a transparent A common electrode 23 is provided.

Of course, the pixel electrode can be provided on the upper substrate and the common electrode can be provided on the lower substrate. 17 is a sealing material. and,
This liquid crystal cell 11 is sandwiched between a first polarizing plate 31 on the observation side and a second polarizing plate 33 having an absorption axis parallel to the absorption axis of the first polarizing plate 31. An element 35 is formed. This liquid crystal element 35 works as a light switching element. Below the liquid crystal element 35, there is an electroluminescent light emitter (EL light emitter) that emits red (R), green (G) and blue (B) light. ), a light source 41 is provided in which R light emitting parts 43a1.0 light emitting parts 43b and eight light emitting parts 43c are formed in a mosaic shape. light source 4
1 is configured with a pixel-shaped light emitting section 43 provided between a transparent electrode 45 and a back electrode 47, and each light emitting section 43a,
43b.

43c and the transparent pixel electrode 21 of the liquid crystal cell 11 are arranged so as to correspond to each other. Transparent electrode 45 and back electrode 47
is connected to a power source 51, and by applying a DC or AC voltage between both electrodes from this power source, the EL phosphor of the light emitting section 43 is made to emit light. 49 represents a substrate.

When a voltage is applied between 43 and 45, the EL of one light emitting section 43
The luminous body (R:・, G:■, B:mu) emits light, R, G,
Light of 83 colors (→, →, →) enters the liquid crystal element 35. Transparent pixel electrode 21 of liquid crystal element 35 and each pixel light emitting section 4
3a, 43b, and 43c correspond, so
By applying a voltage corresponding to a color image signal to the transparent pixel electrode 21 using a thin film transistor (not shown) or the like, light passing through the liquid crystal element 35 can be controlled. The liquid crystal element 35 is constructed by arranging 90@-TN cells between parallel orthogonal polarizing plates, and only the light incident on the liquid crystal element 35 from the pixel light emitting section 43 corresponding to the pixel electrode 21 with the voltage ON is transmitted. The light passes through the liquid crystal element 35 and is observed, and a full-color image is displayed. FIG. 2 shows a state in which R light and G light are transmitted at a ratio of 2=1. kohirotzu→−,E
Since the color of the light emitted from the L light emitting section is observed, it is difficult to obtain a bright and clear color image.

FIG. 3 shows another embodiment of the present invention, in which an EL emission is provided. The color filter 61 is formed of an R filter section 63a, a G filter section 63b, and a B filter section 63c that selectively transmit R light, G light, and B light, respectively. Each of these pixel filter sections 63a, 63b, 63c
is each pixel light emitting section 43a.

43b and 43c, and for example, light from the R light emitting section 43a enters the R filter section 63a. By providing a color filter that transmits light from the EL light emitter in this manner, the following effects can be obtained.

Images with good color balance can be obtained.

(2) It is possible to adjust the hue or dominant wavelength of the emitted light from the R, G, and B pixel light emitters, as well as the saturation and purity of the emitted color.

■ Adjust the brightness of the fluorescent colors of R, G, and B,
Even when the R, G, and B luminances are not necessarily suitable for human observation, these can be adjusted.

FIG. 4 is a model diagram similar to FIG. 2, in which chromatic light from each pixel light emitting section 43a, 43b, 43c of R2O, B passes through each pixel filter section 63a, 63b,
63c and is subjected to transmission/blocking control by the liquid crystal element 35 for color display.

The color filter 61 does not necessarily need to be provided on the substrate 47 of the light source 41, and may be provided at any position through which light from the EL light emitter can pass.For example, on the surface of the polarizing plate 33, on the liquid crystal cell l.
It may be placed on the surface of the transparent substrate 15 in the inside of l, on the transparent pixel electrode 21, on the transparent electrode 23, etc., or it may be provided on a separate transparent substrate and placed above the polarizing plate 31, etc. good.

In the above embodiments, a TN type liquid crystal element was used as the liquid crystal element, but any type of liquid crystal element may be used as long as it functions as an optical switching element. Can be used.

Next, each component will be explained in more detail.

Transparent supports such as glass, polyester, polysulfone, polycarbonate, and plastics such as polypropylene are used as transparent substrates for liquid crystal elements, light sources, and the like. The pixel electrode and common electrode on the transparent substrate may be formed by forming a transparent conductive film such as ITO or NESA by, for example, a PVD method such as vacuum evaporation or sputtering, or a CVD method.The pixel electrode may be formed by a photoetching method or the like. It is formed by patterning, a voltage corresponding to a color image signal is applied by a thin film transistor, etc., and a full color image is displayed by active matrix driving.

For example, in the case of a TN type liquid crystal material, the following materials are used, and these are arranged between the substrates by aligning the upper and lower substrates so that the molecular arrangement is twisted by 90''. .

Guest-host type and dual-frequency drive type liquid crystals are also used.

(1) Liquid crystal compound of p-alkylbenzylidene-P'-cyanoaniline and P-alkoxybenzylidene-P'-cyanoaniline (2) Phenylbenzoate (3) Liquid crystal compound of cyanobiphenyl and cyanoterphenyl CnHsn+i. (n is 3 to 10) CnH moiety (
Yumi' (n is 3 to 7) (4) Cyclohexylcarboxylic acid ester liquid crystal compound (5) Phenylcyclohexane-based and biphenylcyclohexane-based liquid crystal compound (6) Phenylpyridine-based and phenyldioxane-based liquid crystal compound (7) A mixture of the above liquid crystal compounds or a mixture of the above liquid crystal compound and a cholesteric compound.

The transparent electrode of the light source can be formed in the same way as the transparent electrode of the liquid crystal cell, and the back electrode may be transparent or opaque. When using an opaque electrode, a metal electrode in which a metal film is formed on a metal plate or substrate can be used. As the metal electrode, aluminum, copper, silver, gold, etc. can be used. By using a metal electrode, the light from the EL light emitter can be reflected in the direction of the liquid crystal cell by utilizing the high reflectance property of metal for light, and the emitted energy can be efficiently utilized. Further, the color balance can also be improved by utilizing the spectral reflection characteristics of metal. For example, copper and gold have a high reflectance for long wavelength light, ie, yellow to red, and can increase the brightness of EL emitters that emit red light in particular.

The light emitting section is formed by fixing EL light emitters that emit R, G, and B light onto the substrate. The mosaic-like pixel light-emitting portion can be formed using the same method used to manufacture cathode ray tubes for color televisions, for example, and in this invention, there is no need to use phosphor in a vacuum. It can also be configured as a flat surface.

It can be formed using a printing technique similar to gravure three-color printing or silk screen three-color printing. Furthermore, R, G,
The B light emitter pixel portion can also be patterned.

EL luminescent materials are mainly used in powder form, and those that emit red light include rare earth materials such as Y and O.
, S: Eu (yttrium oxide: European)
system, Y, O, :Eu (yttrium oxide: europium) system, (Zn, Cd)S:Ag (zinc sulfide, cadmium: silver doped) system, GaP:In (gallium phosphide: indium dove) system, etc. Examples of those that emit green light include Zn5iO, (Mn) (manganese-doped zinc silicate) system, ZnS:CuA41 (zinc sulfide: steel aluminum doped)' system, and (zn-cd)S:C.
ZnO:Zn (zinc oxide:
Zinc-doped), etc., and those that emit blue light include.

ZnS:Ag (zinc sulfide: silver doped) system.

Examples include (ZnS, Zn0):Ag (zinc sulfide, zinc oxide: silver doped) system, SnO::Eu (tin oxide: European doped), and the like.

Power source 51 is a DC or AC voltage generator.

In the case of AC, 1 from the commercial frequency (50 or 60Hz)
00Hz, preferably 1 to 10kHz
Also, the voltage can range from several volts to several volts, but in order to simplify the power supply,
It is desirable to use commercial frequencies and voltages.

Color filters are produced using photolithographic methods, electrodeposition methods, vacuum evaporation methods, printing methods, etc. Dichroic mirrors and dye filters made of multilayer films of high refractive index materials and low refractive index materials are used, but the latter As a dye for a single dye filter, which is more cost-effective, Lanyl red GG is used for a red dye filter.
d GG) (manufactured by Sumitomo Chemical), Kayanyl Phloxine N
K (Kayanil Floxin NK) (Nippon Kayaku Layer), Suminol milling yellow MR (Suminol sillin) for green dye filters.
gyallov MR) (manufactured by Sumitomo Chemical), Cibacron・
Turkois Blue @T G-E (Cibacr
on turquoise blueTG-E) (
Examples include Cyanine 6B (manufactured by Ciba Geigy) and Cyanine 6B (Nippon Kayaku Layer) for blue pixel filters.

The case where full-color display is performed using transparent pixel electrodes and active matrix driving using TPT or the like has been described above, but other electrode configurations and single-color or multi-color display other than full-color display are also possible.

For example, it is possible to provide a full-color image display by providing electrodes in a stripe pattern in the X-Y direction, pixel EL light emitters corresponding to their intersections, or pixel filters, and multiplex driving. can. The arrangement of the liquid crystal cell, light emitting section, color filter, etc. is as described above. Multiplex driving has a limit in increasing the duty due to crosstalk effects, and from this point of view, the above-mentioned active matrix driving is more advantageous.

Furthermore, color display can be performed using an EL light emitter that emits any single color without using one light emitting unit composed of R, G, and B pixel parts. For example, a plurality of figure 8-shaped segment electrodes are used, and portions corresponding to the individual segment electrodes are provided with light-emitting portions of arbitrary colors or color filters, so that a single color display of red can be performed. Of course, it is also possible to display a multicolor display by arranging light emitting parts of a plurality of colors corresponding to each segment electrode and changing the color depending on the number of digits.

According to the present invention, by controlling and observing the light emitted from the EL light emitter with a liquid crystal device, it is possible to realize a bright and clear color display, and it is also possible to make the entire device thinner. Power consumption can also be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a color liquid crystal display device of the present invention, and FIG. 2 is a model diagram for explaining a color display mechanism using the device. FIG. 3 is a sectional view showing another embodiment of the present invention;
The figure is a model diagram for explaining a color display mechanism using the device.

Claims (1)

[Claims] 1. Electroluminescence in which a liquid crystal element that controls transmission/blocking of light according to image information and a phosphor that emits colored light corresponding to this element are arranged and formed in a mosaic shape. 1. A liquid crystal color display device comprising a light emitting body and arranged so that light from the light emitting body is observed through the liquid crystal element. 2. A liquid crystal element that controls transmission/blocking of light in accordance with image information, an electroluminescent light-emitting body formed by arranging and forming a mosaic of phosphors that emit colored light corresponding to this element, and the light-emitting body a color filter that transmits the light provided at a position through which the light from the light emitting body passes, and is arranged so that the light from the light emitting body is observed through the liquid crystal element. Device.